Question

give an example where work done by a force is negative

Answer 1

work done by friction is negative

Answer 2

Positive and Negative Work. ... Work done by a force is positive if the applied force has a component in the direction of the displacement. When a body is falling down, the force of gravitation is acting in the downward direction. The displacement is also in the downward direction.and it's became negative
hence the force will be negative